This section deals with approaches to delineate the mechanisms by which collagen synthesis/deposition and angiogenic activities are controlled in wounds. The basis of our hypothesis, that ADP-ribosylation influences the activities of collagen promoters and/or transcription proteins, has been provided by our studies conducted in the last grant period. Our aim is now to explore how metabolic conditions in wounds, e.g., high lactate, activate collagen gene transcription and collagen synthesis presumably via ADP-ribosylation. Oxidant insults and heat shock injury also involve ADP-ribosylation. Therefore, as an alternative means to implicate ADPR mechanisms as well as a means to open an area of investigation of wound pathology, we propose to determine whether oxygen radicals, DNA damage/repair, and heat shock proteins modulate collagen synthetase. These studies will be conducted in early passage cultures of human skin fibroblasts. Angiogenesis also appears to be regulated by metabolic state. We have found that release of macrophage angiogenic activity is up-regulated by lactate and hypoxia (factors that lower ADP-ribosylation) and down- regulated by NAD+ (which inhibits poly-ADP ribose synthesis). We propose to study whether the expression and release of the specific angiogenic cytokines, such as vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF) and interleukin-8 (IL-8) and fibrin/fibrin-split products, are regulated by ADP-ribosylation. Bone marrow derived macrophages will be used for these angiogenic response investigations. These studies are expected to provide a firm basis to understand tissue repair as to how and why collagen synthesis and angiogenesis start, slow down, and stop as they do in healthy healing tissue.